Multi-unit blood processor with temperature sensing

ABSTRACT

Method and apparatus for centrifugal blood component separation including temperature sensing in each of a plurality of separation cells. The temperature of unit of bloods over time is recorded. If the temperature of any of the units exceeds a pre-determined maximum, portions of the blood separation device may be cooled. A controller may determine which of the units to process first, generally proceeding from the warmest unit to the coolest. The order of unit processing may be changed during processing. The detected temperature may be used to calibrate a pressure sensor used to predict the volume of a component separated from a composite fluid by predicting the volume of the composite fluid from sensed pressure and predicting the volume of other separated components from sensed movement of the other components to collection bags.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a divisional application of U.S. Utility PatentApplication Ser. No. 13/093,999, filed Apr. 26, 2011, entitled“MULTI-UNIT BLOOD PROCESSOR WITH TEMPERATURE SENSING,” which claimspriority benefit of U.S. Provisional Patent Application Ser. No.61/348,863filed May 27, 2010, entitled “MULTI-UNIT BLOOD PROCESSOR WITHTEMPERATURE SENSING,” both applications are hereby incorporated byreference in their entirety as if set forth herein in full.

FIELD OF THE INVENTION

The present invention relates to apparatus and method for separating atleast two discrete volumes of blood into at least two components each.

BACKGROUND

U.S. application Ser. No. 11/954,388 filed Dec. 12, 2007 describes anapparatus for separating discrete volumes of a composite liquid such asblood into at least two components. The apparatus and method of thisapplication relate to the separation of biological fluids comprising anaqueous component and one or more cellular components. Examples giveninclude: extracting a plasma component and a cellular component(including platelets, white blood cells, and red blood cells) from avolume of whole blood. A component, such as washed red blood cells, mayalso be filtered so as to remove residual prions, white blood cells orplatelets from the red blood cells.

An apparatus for processing blood components that can process at once atleast two discrete volumes of a composite liquid, in particular, twounequal volumes wherein the proportions of the various components of thecomposite liquid that may vary from one discrete volume to another one,is known from U.S. application Ser. No. 11/954,388. A method isdescribed therein for separating at least two discrete volumes of acomposite liquid into at least a first component and a second component.The method comprises at least two separation bags containing twodiscrete volumes of a composite liquid in separation cells mounted on arotor; storing in at least one container on the rotor at least two firstcomponent bags connected to the at least two separation bagsrespectively; separating at least a first component and a secondcomponent in each of the separation bags; transferring at least onefraction of a first separated component into a component bag; detectinga characteristic of a component at a location in each separation bag;and stopping transferring the fraction of the first component upondetection of the characteristic of a component at the first determinedlocation.

SUMMARY OF THE INVENTION

The present invention comprises improvements on a centrifugal bloodseparation device capable of processing a plurality of blood units atthe same time.

The invention includes temperature sensing in each of a plurality ofseparation cells where a discrete unit of blood is to be processed byseparation into components. The measured temperature is communicated toa controller, preferably comprising a microprocessor. The controllerrecords the temperature of the unit of blood over time. If thetemperature of a particular unit of blood exceeds a pre-determinedmaximum, a warning is given. If the temperature of any of the unitsapproaches the pre-determined maximum or another limit, portions of theblood separation device may be cooled to inhibit a rise in temperature.The controller may also determine which of the units to process first,generally proceeding from the warmest unit to the coolest. If differentrates of warming are detected, the order of unit processing may bechanged. The controller also uses temperature information to predictestimated time of processing for a unit or for the combination of allunits of blood currently being processed in the multi-unit separationdevice.

Also disclosed herein is method of predicting the volume of a componentseparated from a composite fluid comprising loading a composite fluidinto a separation cavity on a centrifuge, sensing the fluid pressure inthe separation cavity after the loading step, predicting the volume ofthe composite fluid from the sensing the fluid pressure step, separatingthe composite fluid into at least a first and second component,expressing the first separated component from the separation cavity to acollection cavity, sensing the movement of the first separatedcomponent, predicting the volume of the expressed separated componentfrom the sensing the movement step and predicting the volume of thesecond component remaining in the separation cavity from the predictedvolume of the composite fluid and the predicted volume of the expressedfirst component. Pressure sensors are generally sensitive to variationsin temperature adjacent the pressure sensor. The controller may usetemperature data from a particular unit of blood to calibrate thepressure sensor in the same separation cell.

The method further may comprise sensing, optically with a photocell, theleading edge of the expressed first component by detecting the presenceof fluid in the tubing between the separation cavity and the collectioncavity and sensing, optically with a photocell located near the exit ofthe separation cavity, the trailing edge of the expressed firstcomponent by detecting the presence of components not in the firstexpressed component.

The invention also may include apparatus for predicting the volume of aseparated component using a calibrated pressure sensor, the apparatuscomprising a rotor having at least one separation cavity and at leastone collection cavity for centrifugally separating the composite fluid,which may be whole blood, into a first separated component, which may beplasma, a second separated component, which may be red blood cells, andan optional third separated component, which may be a plateletcomponent; a separation bag containing a composite fluid in theseparation cavity; at least one collection bag in the collection cavity;tubing connecting the separation bag to the at least one collection bag;a temperature sensor for calibrating a pressure sensor; a pressuresensor for detecting a pressure amount due to the composite fluid in theseparation bag; a first sensor for detecting components in the tubing; asecond sensor for detecting changes in separated components in theseparation bag; and a controller for predicting the volume of thecomposite fluid from the amount of pressure sensed by the pressuresensor, predicting the volume of any separated component passing fromthe separation bag through the tubing to the collection bag fromdetection by the first and second sensors, and predicting the volume ofany separated component remaining in the separation bag from the volumeprediction of the composite fluid and the volume prediction of theseparated component passing from the separation bag to the collectionbag.

The apparatus of the invention additionally may use a squeezing systemfor squeezing the separation bag to transfer separated components to thecollection bag. This squeezing system squeezes the separation bag totransfer separated components to the collection bag, wherein the plasmacomponent is transferred from the separation bag to a plasma collectionbag and the platelet component is transferred from the separation bag toa platelet collection bag.

The apparatus also may comprise a pressure sensor, located on the wallof the separation cavity, that detects a pressure amount due to thefluid level of the composite fluid in the separation bag, and atemperature sensor for calibrating the pressure sensor. In addition afirst optical sensor may detect the leading edge of the first separatedcomponent and is located to detect fluid in a tube. A second opticalsensor, located on a wall of the separation cavity, may detect thetrailing edge of a separated component by detecting another component.

Other features and advantages of the invention will appear from thefollowing description and accompanying drawings, which are to beconsidered exemplary only.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of a first set of bags designed forcooperating with a separation apparatus.

FIG. 2 is a schematic view, partly in cross-section along a diametricplane, of the separation apparatus.

FIG. 3 is a top plan view of the separation apparatus of FIG. 2, showingat least part of a set of bags mounted thereon, along with theseparation apparatus valves and sensors.

FIG. 4 is a perspective view of a separation cell, showing a temperaturesensor and a pressure sensor therein.

FIG. 5 is a schematic diagram showing the relationship of FIG.5A andFIG. 5B. FIG. 5A is of a flow chart of a part of a subroutine forutilizing temperature data in a multi-unit blood processor.

FIG. 5B is of a flow chart of a second part of a subroutine forutilizing temperature data in a multi-unit blood processor.

FIG. 6 is a schematic diagram of a plurality of separation apparatusesconnected to a refrigeration unit.

DESCRIPTION OF EMBODIMENT

For the sake of clarity, the invention will be described with respect toa specific use, namely the separation of whole blood into at least twocomponents, in particular into a plasma component and a red blood cellcomponent, or into a plasma component, a platelet component and a redblood cell component. The discrete volume mentioned hereunder willtypically be the volume of a blood donation. The volume of a blooddonation may vary from one donor to another one (for example, 500 mlplus or minus 10% in the United States). Also, the proportion of thecomponents of blood usually varies from one donor to another one. Itshould be understood however that this specific use is exemplary only.

It is understood that white blood cells could further be separated andcollected with suitable volume predictions in accordance with thisinvention.

FIG. 1 shows an example of a set 10 of bags adapted to be used for theseparation of a composite liquid (e.g. whole blood) into at least onecomponent (e.g. plasma, platelets, or both) and a second component (e.g.red blood cells). This bag set comprises a flexible primary separationbag 12 and flexible component or satellite bags 14, 16, 44 and 38connected thereto.

The bag 10 is shown with an asymmetrical manifold 34 forming an E shapeas more fully described below. The manifold 34 is representative inshape in that it is understood that other configurations with varyingnumber of arms or connectors could be used depending on specific use ofthe apparatus, (namely the separation of whole blood into at least twocomponents, in particular into a plasma component and a red blood cellcomponent, or into a plasma component, a platelet component and a redblood cell component or with a washing feature or white blood cellcollection).

When the composite liquid is whole blood, the separation bag 12 has twopurposes, and is successively used as a collection bag and as aseparation bag. It is intended to initially receive a discrete volume ofwhole blood from a donor (usually about 500 ml but can vary as describedabove) and to be used later as a separation chamber in a separationapparatus. The separation bag 12 is flat and generally rectangular. Itis made of two sheets of plastic material that are welded together so asto define there between an interior space having a main rectangularportion connected to a triangular proximal portion. A first tube 18 isconnected to a proximal end of the triangular portion, and a second tube20 and a third tube 22 are connected on opposite sides adjacent thefirst tube 18. The proximal ends of the three tubes 18, 20, 22 areembedded between the two sheets of plastic material so as to beparallel. The separation bag 12 further, optionally, comprises a hole 24in each of its two proximal corners that are adjacent to the three tubes18, 20, 22. The holes 24 may be used to optionally secure the separationbag to a separation cell on a centrifugal blood separation apparatus.

The separation bag initially contains a volume of anti-coagulantsolution (typically about 63 ml of a solution of citrate phosphatedextrose for a blood donation of about 450 ml). The first and thirdtubes 18, 22 are fitted at their proximal ends with a breakable stopper26, 28 respectively, blocking liquid flow therethrough. The breakablestopper is sometimes called a “frangible”. The second tube 20 is acollection tube having a needle 30 connected to its distal end. At thebeginning of a blood donation, the needle 30 is inserted in the vein ofa donor and blood flows into the separation bag 12. After a desiredvolume of blood has been collected in the separation bag 12, thecollection tube 20 is sealed and cut, disconnecting the needle from thebag set 10. Alternatively, previously collected blood may be transferredto the separation bag 12 through the collection tube 20, with or withoutthe use of the needle 30.

The first component bag 14 is intended for receiving a plasma component.The bag 14 is flat and substantially rectangular. It is connectedthrough a plasma collection tube 32 and an asymmetric manifold 34 to thefirst tube 18. The second component bag 16 is intended for receiving aplatelet component. The second component bag 16 is also flat andsubstantially rectangular. It is connected through a platelet collectiontube 36 and the asymmetric manifold 34 to the first tube 18. A thirdcomponent bag 38 is intended to receive a red blood cell component(which may be washed), from the primary bag 12. Red blood cells may bedrained through tube 22, which may include a filter 40, into thirdcomponent bag 38. A breakable stopper 42 or frangible in tube 22 as wellas frangible 28 prevents premature flow of red blood cells into thethird component bag 38.

An optional wash solution bag 44, if used, may initially contain washsolution such as saline or the bag 44 may contain storage solution suchas SAGM if no washing is desired. Wash solution may be transferredthrough a wash solution tube 46 and the asymmetrical manifold 34 by wayof the first tube 18 into the primary bag 12 when the primary bag 12contains high hematocrit blood cells. “High hematocrit” means apercentage of red blood cell volume to total fluid volume of at least 80percent, more preferably 90 percent, and yet more preferably 95 percent.After wash solution is mixed with high hematocrit red blood cells andsubsequently separated, used wash solution may be extracted through thefirst tube 18, asymmetrical manifold 34, and discard tube 46 into a washsolution discard bag 44. The discard bag 44 could also be used tocollect a relatively rare blood component, such as for example,mesenchymal stem cells or some white cells to reduce filter load.

FIG. 2 shows a first embodiment of an apparatus 60 for simultaneouslyseparating by centrifugation four discrete volumes of a compositeliquid. The apparatus comprises a centrifuge 62 adapted to receive fourof the sets 10 of bags shown in FIG. 1, with the four discrete volumesof a composite liquid contained in the four primary separation bags 12;a component transferring means for transferring at least one separatedcomponent from each separation bag into a component bag connectedthereto. The apparatus 60 may further comprise means for washing aresidual high hematocrit red blood cell component.

The centrifuge 62 comprises a rotor 64 that is supported by a bearingassembly 67 allowing the rotor 64 to rotate around a rotation axis 68. Abasket 63, shown in dotted lines in FIG. 2, surrounds the rotor 64 andprovides a safe operating area for the rapidly spinning rotor. Thebasket has a solid circumferential wall 65 and floor 67. A lid (notshown) closes the basket when the centrifuge 62 is operating. The basketmay also have a cooling tube 69 embedded in the floor 67 (as shown) orwall. A cooling fluid, such as water, may be circulated through the tube67 to regulate the temperature of the rotor and the volumes of compositeliquid being processed on the rotor. Preferably, the tube comprises aplurality of circumferential loops with a single inlet and a singleoutlet (not shown), whereby the tube 69 can be coupled to a source ofcooling fluid.

The rotor 64 of the centrifuge 62 comprises a cylindrical rotor shaft 70to which a pulley 72 is connected; a storage means comprising a centralcylindrical container 74 for containing component bags, which isconnected to the rotor shaft 70 at the upper end thereof so that thelongitudinal axis of the rotor shaft 70 and the longitudinal axis of thecontainer 74 coincide with the rotation axis 68. Four identicalseparation cells 78 are coupled to the central container 74 so as toform a symmetrical arrangement with respect to the rotation axis 68. Thecentrifuge further comprises a motor 80 coupled to the rotor by a belt82 engaged in a groove of the pulley 72 so as to rotate the rotor aboutthe rotation axis 68.

Each separation cell 78 comprises a container 84 having the generalshape of a rectangular parallelepiped. The separation cells 78 aremounted on the central container 74 so that their respective medianlongitudinal axes 86 intersect the rotation axis 68, so that they arelocated substantially at the same distance from the rotation axis 68,and so that the angles between their median longitudinal axes 86 aresubstantially the same (i.e. 90 degrees). The median axes 86 of theseparation cells 78 are inclined downwardly with respect to a planeperpendicular to the rotation axis 68.

Each container 84 comprises a cavity 88 that is so shaped anddimensioned as to loosely accommodate a separation bag 12 full ofliquid, of the type shown in FIG. 1. The cavity 88 (which will bereferred to later also as the “separation compartment”) is defined by abottom wall, which is the farthest to the rotation axis 68, a lower wallthat is the closest to the container 74, an upper wall opposite to thelower wall, and two lateral walls. The cavity 88 comprises a main part,extending from the bottom wall, which has substantially the shape of arectangular parallelepiped with rounded corners and edges, and an upper,or proximal, part, which has substantially the shape of a prism havingconvergent triangular bases. In other words, the upper part of thecavity 88 is defined by two sets of two opposing walls convergingtowards the central median axis 86 of the container 84. One interestingfeature of this design is that it causes a radial dilatation of a thinlayer of a minor component of a composite fluid (e.g. the platelets inwhole blood) after separation by centrifugation, and makes the layermore easily detectable in the upper part of a separation bag. This alsoreduces mixing between component layers by providing a gradual,funnel-like transition into the tube. The two couples of opposite wallsof the upper part of the separation cell 78 converge towards threecylindrical parallel channels (not shown), opening at the top of thecontainer 84, and through which, when a separation bag 12 is set in thecontainer 84, the three tubes 18, 20, 22 extend. (Tube 20 along withneedle 30 may be removed before the separation bag 12 is placed in thecontainer 84).

The container 84 also comprises a hinged lateral lid 96, which iscomprised of an upper portion of the external wall of the container 84.The lid 96 is so dimensioned as to allow, when open, an easy loading ofa separation bag 12 full of liquid into the separation cell 78. Thecontainer 84 comprises a locking means (not shown) by which the lid 96can be locked to the remaining part of the container 84. The container84 also comprises a securing or locating means for securing or locatinga separation bag 12 within the separation cell 78. The bag securing orlocating means comprises two pins (not shown) protruding on the internalsurface of the lid 96, close to the top of separation cell 78, and twocorresponding recesses in the upper part of the container 84. The twopins are so spaced apart and dimensioned as to fit into the two holes 24in the upper corners of a separation bag 12.

The separation apparatus further comprises a component transferringmeans for transferring at least one separated component from eachseparation bag into a component bag connected thereto. The componenttransferring means comprises a squeezing system for squeezing theseparation bags 12 within the separation compartments 88 and causing thetransfer of separated components into component bags 14, 16. Thesqueezing system comprises a flexible diaphragm 98 that is secured toeach container 84 so as to define an expandable chamber 100 in thecavity thereof. More specifically, the diaphragm 98 is dimensioned so asto line the bottom wall of the cavity 88 and a large portion of thelower wall of the cavity 88. The squeezing system further comprises aperipheral circular manifold 102 that forms a ring. Each expansionchamber 100 is connected to the manifold 102 by a supply channel 104that extends through the wall of the respective container 84, close tothe bottom thereof. The squeezing system further comprises a hydraulicpumping station 106 for pumping a hydraulic liquid in and out of theexpandable chambers 100 within the separation cells 78. The hydraulicliquid is selected so as to have a density slightly higher than thedensity of the densest of the components in the composite liquid to beseparated (e.g. the red blood cells, when the composite liquid isblood). As a result, during centrifugation, the hydraulic liquid withinthe expandable chambers 100, whatever the volume thereof, will generallyremain in the most external part of the separation cells 78. The pumpingstation 106 is connected to the expandable chambers 100, through arotary seal 108, by a duct 110 that extends through the rotor shaft 70,through the bottom and lateral wall of the central container 74, and,radially outwardly where it connects to the manifold 102. The pumpingstation 106 comprises a piston pump having a piston 112 movable in ahydraulic cylinder 114 fluidly connected via the rotary seal or fluidcoupling 108 to the rotor duct 110. The piston 112 is actuated by abrushless DC motor 116 that moves a lead screw 118 linked to a pistonrod. The hydraulic cylinder 114 is also connected to a hydraulic liquidreservoir 120 having an access controlled by two valves 122 a, 122 b forselectively allowing the introduction or the withdrawal of hydraulicliquid into and from a reciprocating hydraulic circuit including thehydraulic cylinder 114, the rotor duct 110 and the expandable hydraulicchambers 100. A pressure gauge 124 is connected to the hydraulic circuitfor measuring the hydraulic pressure therein.

The container 84 further comprises a pressure sensor 85 in the wall ofthe container. The pressure sensor 85 has a flexible membrane that movesin response to pressure changes in cavity 88 and such membrane isconnected to a pressure transducer to convert such information topressure information. The pressure sensor 85 senses pressure amount dueto the fluid level or head height of fluid in the bag 12. The container84 further includes a second optical sensor 87 in the wall of the wallto detect passage of blood component or interface changes as more fullydescribed below.

A temperature sensor 164 is mounted in each of the separation cells 78where a discrete unit of blood is to be processed by separation intocomponents. The measured temperature is communicated to a controller157, preferably comprising a microprocessor. The controller 157 recordsthe temperature of the unit of blood over time. If the temperature of aparticular unit of blood exceeds a pre-determined maximum, a warning isgiven. If the temperature of any of the units approaches thepre-determined maximum or another limit, portions of the bloodseparation device may be cooled to inhibit a rise in temperature. Thecontroller 157 may also determine which of the units to process first,generally proceeding from the warmest unit to the coolest. If differentrates of warming are detected, the order of unit processing may bechanged. The controller 157 also uses temperature information to predictestimated time of processing for a unit or for the combination of allunits of blood currently being processed in the multi-unit separationdevice.

The separation apparatus further comprises four sets of three pinchvalves 128, 130, 132 that are mounted on the rotor around the opening ofthe central container 74. Each set of pinch valves 128, 130, 132 facesone separation cell 78, with which it is associated. The pinch valves128, 130, 132 are designed for selectively blocking or allowing a flowof liquid through a flexible plastic tube, and selectively sealing andcutting a plastic tube. Each pinch valve 128, 130, 132 comprises anelongated cylindrical body 134 and a head 136 having a jaw 138 forming agap that is defined by a stationary lower plate or anvil 140 and the jaw138 movable between a “load” position, an “open” position, and a“closed” position. The gap is so dimensioned that one of the tubes 32,36, 46 of the bag sets shown in FIG. 1 can be snuggly engaged thereinwhen the jaw is in the open position. The elongated body contains amechanism for moving the jaw and it is connected to a radio frequencygenerator that supplies the energy necessary for sealing and cutting aplastic tube. It is also noted that a tearable seal could alternativelybe used. The pinch valves 128, 130, 132 are mounted inside the centralcontainer 74, adjacent the interior surface thereof, so that theirlongitudinal axes are parallel to the rotation axis 68 and their headsprotrude above the rim of the container 74. The position of a set ofpinch valves 128, 130, 132 with respect to a separation bag 12 and thetubes 32, 36, 46 connected thereto when the separation bag 12 rests inthe separation cell 78 associated with this set of pinch valves 128,130, 132 is shown in dotted lines in FIG. 1. Electric power is suppliedto the pinch valves 128, 130, 132 through a slip ring array 66 that ismounted around a lower portion of the rotor shaft 70.

Rapid placement of tubes, such as tubes 32, 36 and 46, is enhanced bythe ability of the valve jaws in the “load” position to optionally swingcompletely clear of a track or groove adapted to receive a tube.Accurate placement of the tubes is enhanced by the use of theasymmetrical manifold 34. The manifold is comprised of relatively rigidplastic and forms a junction for at least three, preferably four,flexible tubes. Connections for the tubes are asymmetrically spacedaround the manifold. As shown in FIGS. 1 and 3 an embodiment of theasymmetrical manifold 34 comprises an “E” configuration. The “E”configuration comprises a central rigid tube 166 with three stubs 168,171, and 173 connected to tubes 32, 18 and 36, respectively.Diametrically across from the three stubs, a fourth stub 175 connects totube 46 and thence to the auxiliary bag 44. The fourth stub 175 isasymmetrically placed along the tube 166. Because of the asymmetricalshape of the manifold, the manifold can be mounted in a shaped recess onthe central core 150 in only one direction. Each of the tubes 32, 36 and46 of the bag set 10 will consequently be reliably mounted at the propervalve 128, 130, 132. Although the valve jaws swing in the load position,such movement is optional and it is understood that a manifold,depending on shape, can be loaded without such jaw movement.

The separation apparatus also comprises a controller 157 including acontrol unit (e.g. a microprocessor) and a memory unit for providing themicroprocessor with information and programmed instructions relative tovarious separation protocols (e.g. a protocol for the separation of aplasma component and a blood cell component, or a protocol for theseparation of a plasma component, a platelet component, and a red bloodcell component) and to the operation of the apparatus in accordance withsuch separation protocols. In particular, the microprocessor isprogrammed for receiving information relative to the centrifugationspeed(s) at which the rotor is to be rotated during the various stagesof a separation process (e.g. stage of component separation, stage of aplasma component expression, stage of suspension of platelets in aplasma fraction, stage of a platelet component expression, etc), andinformation relative to the various transfer flow rates at whichseparated components are to be transferred from the separation bag 12into the component bags 14, 16. The information relative to the varioustransfer flow rates can be expressed, for example, as hydraulic liquidflow rates in the hydraulic circuit, or as rotation speeds of thebrushless DC motor 116 of the hydraulic pumping station 106. Themicroprocessor is further programmed for receiving, directly or throughthe memory, information from the pressure sensor 124 and from the setsof 87 and 158 sensors (described below) and for controlling thecentrifuge motor 80, the brushless DC motor 116 of the pumping station106, and the four sets of pinch valves 128, 130, 132 so as to cause theseparation apparatus to operate along a selected separation protocol.The microprocessor 157 also receives information from each temperaturesensor 164 and each pressure sensor 85 and from sensors 87 and 158 forvolume determination or prediction.

A first balancing means initially balances the rotor when the weights ofthe four separation bags 12 contained in the separation cells 78 aredifferent. The first balancing means substantially comprises the samestructural elements as the elements of the component transferring meansdescribed above, namely: four expandable hydraulic chambers 100interconnected by a peripheral circular manifold 102, and a hydraulicliquid pumping station 106 for pumping hydraulic liquid into thehydraulic chambers 100 through a rotor duct 110, which is connected tothe circular manifold 102. Under centrifugation forces, the hydraulicliquid will distribute unevenly in the four separation cells 78depending on the difference in weight of the separation bags 12 tobalance the rotor.

FIG. 3 shows a top plan view of the rotor 64. Four symmetrically spacedseparation cells 78 (each with a lid 96) are shown surrounding a centralcore 150, which contains four sets of valves 128, 130, 132 and whichsupports the asymmetrical manifolds 34 and tubes of the bag sets 10. Thecore 150 is supported in the center of the rotor by a spider structurecomprised of four radial support arms 152. The arms 152 define cavities154 between a separation cell 78 and an adjacent set of valves 128, 130,132 on the central core 150. The component bags 14 and 16 (for plasmaand platelets respectively) and the red blood cell component bag 38,with its associated filter 40, are placed in the cavity 154 when the bagset 10 is loaded into the rotor 64. The collection and separation bag12, which initially contains the collected unit of whole blood, isplaced in the adjacent separation cell 78. The auxiliary bag 44, whichmay be used for temporary fluid storage, waste fluid collection orcollection of a rare or small-volume blood component, is placed in awell 156 close to the axis of rotation 68 (see FIG. 3) of the rotor. Thewell 156 is closer to the axis of rotation than at least some of thevalves associated with a single set 10 of bags. The well 156 may becylindrical or rectangular to accommodate a rectangular bag 44, as shownin FIG. 1. The well is positioned such that the processing or primaryseparation bag 12 is located in a relatively high force region of thecentrifugal field produced by the rotation of the rotor, while thecomponent bags 14, 16 are located in a lower force region, and thesmaller wash solution or discard bag 44 placed in the well would be inthe lowest force region. By reason of bag placement in high,intermediate and low force regions of the centrifugal field, air willtend to collect in the wash bag 44 in the well 156. Moreover, a shorterline or tube can be used to connect the small bag 44 to the entire bagassembly. The three placement zones aide in simplifying the bag assemblyand make the process of loading the bag assembly into the rotor easier.

FIG. 3 shows an asymmetric manifold 34 having an “E” configuration (alsoshown in FIG. 1), although other configurations could be used. For eachset of valves, outer valves 128, 132 are shown in “load” configuration,that is, the jaw of the valve does not extend over an adjacent tube,thereby allowing the manifold 34 and tubes to be installed in theirproper configuration on the central core 150. For each set of valves, aninner or center valve 130 is shown in the closed position with respectto tube 46.

A tube sensor 158 is able to detect the presence or absence of liquid inthe tube 18, such as the detection of plasma, as well as to detect bloodcells in a liquid. Each sensor 158 and 87 may comprise a photocellincluding an infrared LED and a photo-detector. Electric power issupplied to the sensors 87, 158 through the slip ring array that ismounted around the lower portion of the rotor shaft 70. In the processof separating blood into component parts, fluid components, such asplasma or platelets, are expressed out of the separation bag 12 in theseparation cell 78 into component bags 14, 16 in the cavities 154. Thesensor 158 may detect the beginning of the plasma flow or the presenceof platelets or red blood cells. In response, the controller 157 mayinterrupt or change the processing for the particular set of bags wherethe new condition was sensed. The second sensor or photocell 87 similarto 158 may also be included in container 84. This sensor 87 is also ableto detect the presence or absence of liquid such as plasma as well asthe presence of platelets or red blood cells. This sensor may be used todetect the trailing edge of a separated layer or fraction.

Since the process of blood separation proceeds at different rates fordifferent blood units, the volumes and weights of fluids in differentbags and locations on the rotor will differ. A second balancing means160 balances the rotor when the weights of the components transferredinto the component bags 14, 16 in the cavities 154 are different. Forexample, when two blood donations have the same hematocrit and differentvolumes, the volumes of plasma extracted from each donation aredifferent, and the same is true when two blood donations have the samevolume and different hematocrit. The second balancing means comprises abalance assembly or ring 160, more particularly described in U.S. patentapplication Ser. No. 11/751,748, filed May 22, 2007, and incorporatedherein by reference. The balancing apparatus of the separation apparatuscomprises one or two balancing assemblies, each including a series ofponderous satellites or balls that can move freely on a specificcircular orbit centered on and perpendicular to the axis of rotation ofthe rotor. The housing comprises a container for spherical ponderoussatellites (balls) 162, which are housed in a cylindrical outer race, inwhich the balls slightly engage, and on which they roll, when the rotorrotates. The balancing means 160 comprises a plurality of balls. Whenthe balls are in contact with each other, they occupy a sector of thering of about 180 degrees. The balancing means 160 also comprises adamper or dampening fluid or element for providing resistance to themovement of the balls.

The method of using the apparatus described above will now be described.

Each procedure to separate composite fluid or whole blood begins withcollection of the whole blood or fluid into bag 12 of bag set 10. Thebag set 10 is then loaded onto apparatus 60. Before loading the bag set10, needle 30 and tube 20 may be removed by sterile welding or otherprocedure. The bag 12 containing the composite fluid or whole blood isplaced in the cavity 88. This may be done for each cavity 88 of theapparatus 60. The collection bags and other fluid bag, if any, is placedin the respective cavity 154 or 156. The rotation of the rotor beginsand the rotor is rotated until it reaches an rpm suitable forseparation, (for example 1800 to 3200 rpm).

The temperature sensors 164 in each of the separation cells 78 monitorstemperature of the blood in the separation bag 12 throughout theprocedure, as illustrated in FIG. 5. A temperature subroutine 170 isimplemented in the controller 157. After the bags have been loaded 172into the apparatus, temperature of each of the bags is measured 174. Thecontroller 157 records 176 the temperature for each separation bag 12. Ahistoric record of temperature for each bag will be maintained inlong-term memory such that the record may be accessed by or reported toan operator. In particular, the controller 157 tests 178 each separationbag 12 for a high temperature exceeding a high temperature limit. If thehigh temperature limit is exceeded, the controller initiates cooling180, for example, by allowing cold water to circulate through tubes 69in the basket 63 or housing surrounding the centrifuge rotor 64. Ifdesired, a second high temperature limit may be provided, which mightindicate the possibility of heat damage to the blood components. If thesecond high temperature limit were exceeded, an alarm would be given tothe operator. The controller 157 further tests 182 for a low temperaturebelow a predetermined low temperature limit. If the temperature in anyseparation bag 12 falls below the low temperature limit, an alarm 184would be given to the operator.

Cold water, or another cooling fluid, may be provided from arefrigeration unit 220 to multiple separation apparatus or units 60, asshown schematically in FIG. 6. Input lines 222 carry cooling fluid tothe units 60 from the refrigeration unit 220 and output lines 224 returnthe fluid to the refrigeration unit 220. Other known means of coolingcould also be used. The cooling fluid could be water drawn from a watersupply and discarded after use without re-circulation. In eachseparation unit 60, the on-board controller 157 opens or closes valves(not shown) to allow cooling fluid to circulate in a selected unit 60.

When the temperatures at each separation bag 12 have been sensed, atemperature correction can be applied to calibrate 186 the pressuresensors 85 in each separation cell. Pressure sensors useful in thepresent invention are frequently coupled to a Wheatstone bridge, in aknown manner, and are known to be sensitive to variations in temperaturein the vicinity of the pressure sensor. Given the detected temperatureof the separation bag, the controller 157 can apply a correction factorfor the particular pressure sensor according to manufacturer'sspecifications.

The controller 157 can also set 188 the processing order of theseparation cells. In general, the warmest blood unit will be expected toseparate and be processed more quickly than cooler units. The controller157 may set an order for processing the units of blood from the warmestto the coolest unit.

Periodically, the apparatus will re-check 190 the temperature in each ofthe separation bags 12. The controller records 192 the new temperaturesin memory. As above, the controller 157 tests 194 each separation bag 12for a high temperature exceeding the high temperature limit andinitiates cooling 196, if appropriate. The controller 157 also tests 198for a low temperature below the low temperature limit. If thetemperature in any separation bag 12 falls below the low temperaturelimit, an alarm 200 would be given to the operator. If there is anychange in temperature of any of the separation bags, the controllerwould re-calibrate 202 the associated pressure sensor.

The controller checks 204 for the completion of processing in acurrently-processed separation bag 12 and continues to periodicallyre-check the bag temperatures until processing of the current bag iscomplete. The controller then determines 206 whether all the bags havebeen processed. If not, the controller may re-order 208 the processingorder of the remaining bags, based on the current temperatures of theseparation bags 12. Some changes in temperature may be expected duringprocessing as a result of variations in the volumes and compositions ofthe blood components in the different bags, as well as variations intemperature on the rotor or in hydraulic fluid used to move the bloodcomponents, as has been described herein.

If processing of all separation bags has been completed for all bags, asmore completely described below, a report history of temperature changesfor each separation bag 12 may be generated 210 and stored in memory,and the subroutine 170 may be completed 212.

During the operation of the temperature subroutine 170, as describedabove, a pressure sensing value at a designated rpm is provided bypressure sensor 85 to the control unit 157. The valves may be opened orclosed during the pressure sensing step. The fluid pressure measurementis used by the controller to predict the volume of the composite fluidor whole blood. The pressure amount corresponds to the fluid level orhead height and thus corresponds to the composite fluid volume. Asrotation continues, valve 128 opens or remains opens and plasma, theleast dense component in whole blood, flows into bag 14. The hydraulicfluid from reservoir 120 flows through 110 and 104 and under bladder ordiaphragm 98 to squeeze bag 12 to facilitate plasma transfer to bag 14.Photocell 158 optically sees the leading edge of the plasma flow andprovides such information to controller 157. When photocell or sensor 57senses a cellular component approaching tubing 18 from the top of bag12, it also provides the information including the trailing edge of theplasma interface to the controller 157. The controller sends a signal toclose valve 128 and open valve 132 for cellular component. The hydraulicflow rate corresponds to the fluid flow rate into the collection bag 14and 16. From this flow rate and the sensor signals 57, 158 determiningthe start (leading edge) and end (trailing edge) of the plasmacollection, the volume of plasma can be predicted.

Sensors 57 and 158 further can sense the change of cellular componentfrom, for example, platelets to red blood cells. Photocell 158 indicatesthe leading edge of the platelet layer with photocell 57 indicating thetrailing edge. This sensing of an interface change between differentlayers or sedimented blood components will cause the controller tosignal valve 132 to close and the end of the platelet collection. Theleading edge sensor 158 signal indicating platelets along with thetrailing edge sensor 57 signal indicating the end of the platelet layeris provided to the controller, along with the fluid flow rate, todetermine or estimate the volume of platelets transferred. The estimatedplasma volume as well as the estimated platelet volume along with theinitial whole blood volume estimate can be used by the controller toprovide an estimate of the remaining component or components such as redblood cells in bag 12.

If it is desired to add wash solution or storage solution into theremaining red blood cells, the hydraulics 112 may be pulled back todrain out from under diaphragm or membrane 98 to release the squeezingpressure on the previously squeezed bag 12. Valve 130 may be opened andwash or storage solution may be introduced from bag 44 through tubing 46to bag 12.

If washing is the desired protocol, the wash solution may be mixed withthe red blood cells and resulting supernatant can be expressed back tobag 44 using the hydraulic fluid to squeeze bag 12 for the transfer.

If the storage solution is added from bag 44, the centrifuge will bestopped. The bag set 10 may be removed from the centrifuge and alltubing but 22 can be discarded.

Storage solution can be also gravity drained from bag 38 through filter40 to mix with remaining red blood cells in bag 12.

Valves 128, 130 and 132 can provide heat sealing of the tubing 32, 46and 36. Any remaining tubing can also be heat sealed by the operator forremoval leaving bag 12, tubing 22, filter 40 and bag 38 remaining. Theresidual product, such as red blood cells and storage solution, isdrained from bag 12 to 42. Frangibles 28 and 42 are opened and bag 12,is elevated to gravity drain the red blood cells through leukoreductionfilter 40 to bag 38.

The above procedure is only exemplary to describe the invention as it isunderstood that variations can occur. Although sensors 57 and 58 aredescribed, it is understood that sensor 158 or sensor 57 only may beused to detect a leading edge or a trailing edge or an interface change.Also, additional optical sensors may be provided around container 84similar to sensor 57 to detect fluid or cells.

It will be apparent to those skilled in the art that variousmodifications can be made to the apparatus and method described herein.Thus, it should be understood that the invention is not limited to thesubject matter discussed in the specification. Rather, the presentinvention is intended to cover modifications and variations.

The invention claimed is:
 1. An apparatus for separating bloodcomprising a rotor having a plurality of separation cavities and aplurality of collection cavities for centrifugally separating aplurality of distinct units of blood into first separated components andat least second separated components; a plurality of separation bags,each containing a unit of blood and adapted to be disposed in one of theplurality of separation cavities; a plurality of collection bags, eachadapted to be disposed in one of the plurality of collection cavities;tubing connecting one of the plurality of separation bags to one of theplurality of collection bags; a plurality of temperature sensors fordetecting a temperature of blood in the plurality of separation bagsdisposed in the plurality of separation cavities; a controllercomprising a microprocessor programmed to: receive sensed temperaturesof the units of blood; and in response to receiving sensed temperatures,determining an order for processing units of blood in the plurality ofseparation bags.
 2. The apparatus of claim 1 wherein the microprocessoris further programmed to: change the order for processing units of bloodin response to sensed changes in the temperatures of the units of blood.